T-131: wrap T-99 with governance amendments and shell-usage docs

D-56 and D-68 gain dated implementation-notes amendments pointing at
the eight T-99 slices (T-124 server through T-131 wrap-up) and the
D-70/71/72/73 records the work spawned. D-68's main Decision text
swaps "Transport deferred to Q-33" for the closed reference to D-73.

CONTRIBUTING.md gains a "Running clide from the shell" section
covering the verb surface, exit-code contract per D-68, and
`/ide` MCP discovery via `~/.claude/ide/<pid>.lock`. governance/
README.md picks up the D-73 entry it was missing.

T-119 moves out of backlog (its IPC dispatch path now exists);
T-120 gains a 2026-05-19 re-scope note pointing the typed schema
framework at the now-real argv grammar / wire contract. T-99
itself transitions to done.

Co-Authored-By: Claude <noreply@anthropic.com>

CHANGELOG.md

@@ -53,6 +53,9 @@ heading, and (b) bumping `pubspec.yaml` `version:` in the same commit.
   "always open this project on launch" checkbox in welcome's RECENT
   list sets a sticky-startup flag; if exactly one project has it,
   that one opens directly. Two or more, or none ⇒ picker (T-115).
+- CONTRIBUTING.md "Running clide from the shell" section — documents
+  the shell verbs, exit-code contract per D-68, and Claude Code
+  `/ide` MCP discovery via `~/.claude/ide/<pid>.lock` (T-131).
 
 ### Changed
 
@@ -60,6 +63,9 @@ heading, and (b) bumping `pubspec.yaml` `version:` in the same commit.
   Flutter UI's `DaemonClient` now talks to its own `IpcServer` over
   the same per-workspace Unix socket the C `clide` client uses — one
   transport, one contract.
+- D-56 / D-68 amended with implementation notes — both decisions now
+  link out to T-99's eight slices (T-124–T-131) and the D-70/71/72/73
+  records they spawned (T-131).
 
 ### Deprecated